GFAS-DPOL

Ground-based Fog & Aerosol Spectrometer with Polarization Detection

The GFAS-DPOL combines a high-sensitivity forward & back scatter intensity particle size measurement with a polarization detection measurement and a wind direction and wind-speed measurement. It is used for understanding fog formation, development and decay, and deriving number concentration, liquid water content, extinction coefficient and visibility in warm and mixed-phase fog.

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Measure the properties of complex fog/smog particles to better understand their composition and forecast their occurrence

The shape factor is used to differentiate liquid droplets from ice crystals, dust particles or ash from biomass burning. The complex refractive index determines if fog droplets are mixed with either dissolved or insoluble material.

Instrument Features include integrated sample aspiration pump, integrated control & data logging computer, integrated ultrasonic anemometer for wind-speed & -direction, Self-orientation to wind direction, Power filter and transient suppressor

Particle light-scattering and polarization detection

  • GFAS-DPOL single particle optical spectrometer that is a ground-based version of Droplet’s airborne Cloud and Aerosol Spectrometer with Polarization
  • A forward-scattering optical spectrometer accepts and sizes only particles that pass through a region of the laser beam with uniform power.
  • Forward-scattered light is collected, directed through a 50/50 optical beam splitter, then measured by photodetectors to determine size and depth of field.
  • The shape factor is used to differentiate liquid droplets from ice crystals, dust particles or ash from biomass burning.
  • The complex refractive index determines if fog droplets are mixed with either dissolved or insoluble material.

ParameterSpecification
Measured Parameters Forward & back scatter measurements Polarization detection measurements
Auxiliary Parameters Wind speed Temperature Pressure
Derived Parameters Particle diameter Particle number concentration Polarization ratio Liquid water content Effective diameter Median volume diameter
Particle Size Range 0.5-50 µm diameter
Number of Size Bins 30
Typical Sample Area 0.24 mm²
Sample Flow Volume 1 m3/min
Sampling Frequency Standard Data Rate: Selectable, 0.04 sec to 20 sec PBP Data Rate: No limit until particles are coincident
Refractive Index Non-absorbing, 1.33 (the industry standard for water)
Light Collection Angles Forward: ~3.5º - 12º Back: ~ 183.5° - 192°
Data System Interface Ethernet
Environmental Operating Conditions Temperature: -40 to 45 °C (except in heavy icing conditions) Relative Humidity: 0 - 100%, non-condensing Altitude: 0 - 4,000 meters
Probe Dimensions 63 cm H x 39 cm W x 75 cm L
Power Requirements Universal Power Supply: 85 – 265 VAC / 50/60 Hz / 600 W

The Lifecycle Care Program ensures GFAS-DPOL integrity and performance vital to your research mission for 3 years or 3 calls (whichever comes first). When conducting complex and time intensive laboratory or field measurements it is critical to avoid down time, and ensure data collection accuracy. The program consists of 3 key deliverables for each year or call:

  • Instrument Logistics
  • Instrument Integrity
  • Instrument Performance

Lifecycle Care Program Includes:

LOGISTICS

  • Shipping to and from Droplet Measurement Technologies facility
  • Customs handling, including CARNET ATA if required

INTEGRITY

  • Incoming instrument evaluation and health check

PERFORMANCE

  • Software and firmware validation
  • 100%-unit functionality test
  • Calibration data
  • Calibration report
  • Certificate of calibration

At times, our technician might discover an instrument issue, which might not be covered by the Lifecycle Care Program or by our product warranty. In such case we will reach out to you with a service & repair estimate to allow you to provide us with the next steps of action.

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Speak with one of our scientists or experts at Droplet Measurement Technologies today to discover solutions that can power your research.

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